Double-component silicone structural sealant for low-temperature rapid vulcanization bonding building

Abstract

The invention discloses a preparation method and application of a low-temperature rapid vulcanized and bonded two-component silicone structural sealant for buildings. The invention belongs to the technical field of silicone sealants. The bi-component silicone structural sealant for buildings is prepared from hydroxyl-terminated polysiloxane, nano calcium carbonate, precipitated white carbon black, a cross-linking agent, a tackifying silane coupling agent, a catalyst, carbon black and the like. A main paste component A with stable performance is prepared through a double-screw continuous production line, and raw materials such as an amino silane coupling agent oligomer and an alkoxy silane oligomer are subjected to vacuum mixing through a planetary mixer to prepare a low-temperature rapid vulcanizing agent component B. After the bi-component silicone structural sealant for the building is vulcanized for 24 hours under the low-temperature environment condition, the tensile adhesive strength of the bi-component silicone structural sealant meets the GB16776 forced standard of the silicone structural sealant for the building, the highest adhesive strength value of the bi-component silicone structural sealant reaches about 70% after the bi-component silicone structural sealant is cured for 14 days under the same condition, and the bi-component silicone structural sealant is particularly suitable for production and installation of building glass curtain walls in winter. The method is suitable for building-related industries.

Description

Technical Field

[0001] The invention relates to the technical field of adhesives, in particular to a low-temperature fast-vulcanizing two-component silicone structural sealant for building bonding. Background Art

[0002] Silicone structural sealant for construction is mainly used for the second bonding and sealing of glass, aluminum alloy sub-frame and insulating glass. The purpose is to ensure the bonding and sealing of glass and aluminum alloy sub-frame (glass), and to ensure the reliable fixation of glass and sub-frame (glass). Secondly, due to its elastic bonding, it is guaranteed that the bonding will not be damaged due to the deformation of glass and aluminum alloy sub-frame (glass) itself and external factors. Finally, silicone structural sealant has good weather resistance and ensures the long-term stability of its own performance. Therefore, silicone structural sealant for construction has been widely used in curtain wall glass.

[0003] Silicone structural sealants for construction are divided into two packaging forms: single-component and two-component. Single-component packaging is convenient and quick to use. You can use it by opening the single-component packaged silicone structural sealant, but the single-component silicone structural sealant needs to be exposed to moisture in the air to start vulcanization from the outside to the inside. Under normal temperature conditions (25°C, 50% relative humidity), the curing time is as long as 21 days. In order to shorten the curing time, a two-component packaged silicone structural sealant was developed. After the two components are evenly mixed, the cross-linking agent and the viscosity-increasing silane coupling agent start the dealcoholization condensation reaction from the inside to the outside at the same time under the action of the catalyst and trace moisture. Since it is an overall vulcanization, the curing time is only 14 days. It greatly shortens the curing time, reduces the production turnover site, and improves production efficiency.

[0004] Whether it is a single-component or double-component silicone structural sealant, its vulcanization process cannot be separated from the participation of water. During the production process of single-component silicone structural sealant, it must be free of water to ensure storage stability. After it is squeezed out of the sealed packaging container and exposed to water in the air, it begins to undergo condensation polymerization and eventually vulcanizes into a bonding elastomer. The main paste of the two-component silicone structural sealant contains a trace amount of water. Once the two components are evenly mixed, under the action of the catalyst and water, the cross-linking agent and the tackifying silane coupling agent in the curing agent react with the base resin and become a bonding elastomer through condensation polymerization.

[0005] Due to the different forms of reaction between single-component and two-component silicone structural sealants and water, the overall vulcanization rate of single-component silicone structural sealants is relatively slow, and its vulcanization degree is greatly affected by the external temperature and the moisture content in the air; while the two-component silicone structural sealants contain trace amounts of moisture, so their vulcanization degree is greatly affected by the external temperature, and the influence of the moisture content in the external air is relatively small. Therefore, in order to ensure the stable vulcanization rate and bonding performance of two-component silicone structural sealants, in addition to considering the influence of the external temperature, the stability of its own moisture content is crucial.

[0006] At present, the traditional process for producing two-component silicone structural sealants is to control the moisture content in the main paste by heating and dehumidifying or not heating according to the moisture content of calcium carbonate during the dispersion of calcium carbonate. The moisture content of calcium carbonate varies greatly due to the effects of calcium carbonate ex-factory, storage, and ambient temperature and humidity. In addition, the water in calcium carbonate is adsorbed water, which is difficult to exist evenly in oily polysiloxane for a long time. The vulcanization performance of two-component silicone structural sealants fluctuates greatly, especially under low temperature conditions, where its vulcanization rate and bonding performance are greatly affected.

[0007] The stability of water content in two-component silicone structural sealant: first, the water is evenly dispersed in the main paste, and second, the main paste will not precipitate, aggregate and evaporate due to the poor compatibility between water and silicone during long-term storage. The best solution is to add an oil-in-water emulsion polymer to the main paste to improve the uniform dispersion of water inside it, and at the same time, stably store water in the colloid in the form of oil-in-water. Patent CN111944476A adds oil-in-water emulsion, and the internal curing rate is adjustable and controllable and anti-bulging after construction. Patent CN113684003A adds alcohol water to control the water content to 2000-4000ppm, and the deep curing speed is fast. Patent CN118027886A directly adds water when the main paste is stirred and mixed in a planetary mixer to obtain a two-component silicone rubber that can be deeply cured.

[0008] Although the method of adding water-in-oil emulsion is effective in intermittent production, it cannot be effectively implemented for twin-screw continuous production lines. For this reason, precipitated silica is organically combined with nano calcium carbonate in advance, and the water content in the main paste is effectively controlled at about 800±50ppm through twin-screw mixing and grinding, heating vacuum and cooling filtration processes. The reasons for choosing precipitated silica to replenish water are: first, precipitated silica can be fully mixed with 107 glue; second, water and the hydroxyl groups on the surface of silica form stable bound water through hydrogen bonds, unlike calcium carbonate, which is adsorbed water and can be easily removed by heating and vacuuming; third, the trace amount of bound water in precipitated silica will not precipitate and volatilize due to long-term storage of the main paste. Patents CN104673180A and CN105647462 both use a twin-screw continuous production process to produce the main paste component A, but do not consider the effect of moisture content on the vulcanization of the rubber compound as in their patents CN111944476A and CN113684003A.

[0009] In order to reduce the influence of humidity in the external environment, during the production process of the main paste of component A, the paste can be treated to a nearly water-free state through a pre-heating vacuum process, and then the internal water content can be controlled by quantitatively adding water. Patent CN111944476A uses such a process to add water-in-oil emulsion, and the internal curing rate is adjustable and controllable and anti-bulging after construction. However, this process requires an additional water replenishment process, which is acceptable for small-scale production. For large-scale production, the labor intensity is high, and a special water-in-oil emulsion needs to be prepared in advance. A large amount of energy is required for heating, dehumidification and water replenishment, and a long time is required to cool the rubber before water replenishment. Although this method is time-consuming and labor-intensive, the product performance is stable.

[0010] In order to make the best of its strengths and overcome its weaknesses, a twin-screw continuous production line is adopted. On the basis of the existing production formula, the content of precipitated silica is appropriately increased. Through the twin-screw mixing and grinding, heating and vacuuming (dehumidification and defoaming), cooling and filtering (removal of mechanical impurities), the produced rubber compound can be packaged and shipped immediately, ensuring the stable and reliable performance of the product during the shelf life.

[0011] Temperature has a great influence on chemical reactions. Generally, for every 10°C increase in temperature, the reaction rate will increase by 2 to 4 times. Conversely, for every 10°C decrease in temperature, the reaction rate will slow down by 2 to 4 times. Therefore, for any silicone structural sealant used in construction, the temperature and relative humidity of the external environment play a very important role in affecting its own vulcanization degree.

[0012] In order to reduce the effect of temperature on the reaction rate, the first is to increase the number of activated reaction molecules to reduce their dependence on temperature; the second is to shorten the reaction steps in the reaction process, increase the reaction rate, and thus reduce the effect of the reaction on temperature; the third is to increase the amount of catalyst used in the reaction process, reduce the reaction energy barrier, and then increase the reaction rate under low temperature conditions; the fourth is to increase the necessary conditions required for the reaction, such as the trace amount of water mentioned above, which has the effect of promoting the acceleration of the reaction. The fifth is to change the acidity and alkalinity of the reaction and increase the reaction activity. For example, the addition of alkaline amino groups can quickly promote the hydrolysis of alkoxy groups and then the condensation polymerization reaction with silanol groups.

[0013] It is generally difficult to increase the number of activated reaction molecules, but it can be controlled by shortening the reaction steps, that is, prepolymerizing or reacting the substances involved in the reaction to form intermediates, and then further reacting them to form the desired substances.

[0014] The selection of crosslinking agent and adhesion-enhancing silane coupling agent oligomer reduces the generation of hydroxyl groups by the reaction of small molecule crosslinking agent and silane coupling agent with water, and then the hydroxyl groups undergo condensation reaction with the hydroxyl groups of 107 glue or the hydroxyl groups on the surface of the bonding substrate to form crosslinking vulcanization and bonding. Since the small molecules are pre-condensed into oligomers, the oligomers react with water to generate hydroxyl groups, which then undergo effective condensation reaction with the hydroxyl groups of 107 glue or the hydroxyl groups on the surface of the bonding substrate, thus avoiding the condensation reaction between the hydroxyl groups themselves and improving the degree of vulcanization and bonding strength. At the same time, the increase in the number of adhesion-enhancing amino groups on the surface of the substrate promotes the rapid condensation polymerization reaction, greatly improves the tensile bonding strength, reduces its dependence on temperature, and shortens the curing time of the two-component silicone structural sealant vulcanization.

[0015] Increasing the amount of catalyst used can greatly shorten the reaction time under the same temperature conditions, but in low temperature conditions, blindly increasing the amount of catalyst used has little effect.

[0016] Although the initial tackifying force of patent CN114133912 is greatly improved, its tensile bond strength is still very low and cannot meet the actual use requirements. Patent 112812736 has a higher 24-hour initial tensile bond strength, but the sample must be prepared at room temperature (23°C, relative humidity 50%) to meet the GB16776-2005 standard requirements.

[0017] Reasonable combination of adhesion-enhancing silane coupling agents is beneficial to improving tensile bonding strength. The combination of amino and epoxy group silane coupling agents is beneficial to the ring opening of epoxy groups, increasing the strength and adaptability of the adhesive to the substrate. The combination of primary amines and secondary amines is preferred, which is very beneficial for promoting the ring opening and adhesion of epoxy groups under low temperature conditions.

[0018] The production of glass curtain walls is generally carried out inside the factory workshop. The glass and the aluminum alloy sub-frame are bonded by applying silicone structural sealant. After a period of vulcanization and curing, the glass and the aluminum alloy sub-frame are completely and firmly bonded by the silicone structural sealant. After the rubber cutting test meets the standards, it is transported to the construction site and installed on the wall. During the vulcanization and curing period, especially right after the glue is applied, it is strictly forbidden to move the aluminum alloy sub-frame: first, to prevent the bonding from being loose, and second, to prevent the bonding size from changing, resulting in the inability to install.

[0019] Two-component silicone structural sealant usually reaches 100% cohesive failure in 1 to 7 days (25°C, 50% humidity), and GB16776-2005 "Silicone Structural Sealant for Building" stipulates that the vulcanization curing time of two-component silicone structural sealant is 14 days. Combined with GB / T32369-2015 "Determination of the degree of curing of sealants" and JGJ102-2003 "Technical Specifications for Glass Curtain Wall Engineering": Two aluminum alloy or stainless steel glass curtain wall support strips should be installed at the lower end of each glass of the hidden frame or semi-hidden frame glass curtain wall, and the number and position of the support strips must be installed according to the design requirements.

[0020] Glass curtain wall support strips: A support structure installed at the bottom of the glass curtain wall or along the perimeter of the curtain wall. Its main function is to support the weight of the glass curtain wall to ensure the stability and safety of the curtain wall. As the exterior wall of the building, the glass curtain wall needs to bear its own weight and external wind loads. As a supporting structure, the support strips can effectively disperse and transfer these loads to ensure the safety and stability of the glass curtain wall. Secondly, the support strips are connected to the main structure of the building to fix the glass curtain wall and prevent the curtain wall from moving or deforming due to various reasons.

[0021] Based on the above, in low temperature environment, especially in the construction process of glass curtain wall in winter, in order to meet the needs of the project, according to the test and actual project installation experience, after the two-component silicone structural sealant is applied for 24 to 72 hours, the tensile bonding strength between the glass and the aluminum alloy sub-frame only needs to meet the GB16776 standard and reach about 70% of the maximum bonding strength value after 14 days of curing under the same conditions before installation and construction. Summary of the invention

[0022] The invention provides a preparation method for improving the curing rate and initial tensile bonding strength of a two-component silicone structural sealant for construction under low temperature conditions, especially under winter construction conditions. The rapid curing bonding of the two-component silicone structural sealant for low-temperature construction provided by the invention has a faster curing rate and higher bonding strength under low temperature conditions (0-10°C).

[0023] The present invention provides a two-component silicone structural sealant for bonding and sealing building glass curtain walls suitable for rapid vulcanization bonding under low temperature conditions, comprising a component A main paste and a component B rapid vulcanizing agent;

[0024] The main paste of component A is prepared by mixing the following raw materials in parts by weight:

[0025]

[0026] The B component rapid vulcanizing agent is prepared by mixing the following raw materials in parts by weight:

[0027]

[0028] Preferably, the viscosity of the 107 glue is 5000-80000 mPa·s, and the viscosity of the dimethyl silicone oil is 100-500 mPa·s.

[0029] Preferably, the nano calcium carbonate is nano calcium carbonate whose surface is treated with stearic acid.

[0030] Preferably, the water content of the precipitated silica is about 10%.

[0031] Preferably, the crosslinking agent is composed of alkyltrimethoxysilane or alkyltriethoxysilane oligomer, hexamethoxydisilylethane or hexaethoxydisilylethane;

[0032] Alkyl trimethoxysilane oligomer selection: one or more combinations of methyl trimethoxysilane, ethyl trimethoxysilane or propyl trimethoxysilane oligomer;

[0033] The alkyltriethoxysilane oligomer is selected from one or more combinations of methyltriethoxysilane, ethyltriethoxysilane or propyltriethoxysilane oligomers.

[0034] Preferably, the adhesion-enhancing silane coupling agent is a compound of an oligomer containing an amino silane coupling agent and a silane coupling agent containing an epoxy group;

[0035] Selection of amino-containing silane coupling agent oligomers: γ-aminopropyltrimethoxysilane, methylγ-aminopropyldimethoxysilane, γ-aminopropyltriethoxysilane, methylγ-aminopropyldiethoxysilane, N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane, methylN-(β-aminoethyl)-γ-aminopropyldimethoxysilane, N-(β-aminoethyl)-γ-aminopropyltriethoxysilane, hydrolyzed oligomers of methylN-(β-aminoethyl)-γ-aminopropyldiethoxysilane and bis-(3-trimethoxysilylpropyl)amine, a compound of one or more oligomers of bis-(3-triethoxysilylpropyl)amine;

[0036] Selection of epoxy group-containing silane coupling agent: one or more combinations of γ-glycidyloxypropyl trimethoxysilane, methyl γ-glycidyloxypropyl dimethoxysilane, γ-glycidyloxypropyl triethoxysilane, and methyl γ-glycidyloxypropyl diethoxysilane;

[0037] Aminosilane coupling agent hydrolyzed oligomer: aminodialkylsilane: epoxysilane = 2:1:2 (weight ratio).

[0038] Preferably, the method for synthesizing the amino-containing silane coupling agent oligomer comprises the following steps:

[0039] (1) first add a polar solvent into a reaction vessel;

[0040] (2) then adding the aminosilane coupling agent into the reaction vessel and starting the stirrer to allow the silane coupling agent to fully dissolve;

[0041] (3) adding a solution of pure water dissolved in a polar solvent dropwise into a reaction vessel, controlling the dropping speed so that the reaction temperature of the hydrolysis polymerization of the aminosilane coupling agent is maintained in the range of 45 to 50° C.;

[0042] (4) After the polar solvent solution containing water is added dropwise, the temperature of the solution in the reaction container is raised to about 90° C. and reacted for 2 hours;

[0043] (5) Finally, the solution temperature was raised to about 120° C., and the reaction was continued for 2 hours. The vacuum degree was controlled to be lower than -0.09 MPa, and the solution was vacuumed to obtain an aminosilane coupling agent oligomer with a degree of polymerization of 6.

[0044] Preferably, the catalyst is organic tin and organic titanium;

[0045] Selection of organotin catalyst: one or more of dibutyltin dilaurate, dioctyltin dilaurate, dimethyltin dilaurate, dibutyltin diacetate and dibutyltin bis(acetylacetonate);

[0046] The organic titanium catalyst can be selected from one or more of isopropyl titanate, n-butyl titanate, diisopropyl diacetoacetate, and 1,3-propylene diacetoacetate.

[0047] The present invention also provides a method for preparing the above-mentioned two-component silicone structural sealant for bonding and sealing building glass curtain walls under low temperature conditions, comprising the following method:

[0048] Preparation method of main paste of component A:

[0049] Using a twin-screw continuous production line, 107 glue, dimethyl silicone oil, nano calcium carbonate and precipitated white carbon black are automatically weighed by automatic metering equipment and then transported to a twin-screw machine through a closed pipeline. After twin-screw mixing and grinding, high-temperature heating at 120±5℃, a vacuum degree lower than -0.08MPa, vacuuming (dehumidification and defoaming), cooling and filtering (removal of mechanical impurities), a fine main paste component A containing trace and stable deep rapid vulcanization accelerator moisture is obtained.

[0050] Preferably, the moisture content in the main paste is controlled at about 800±50ppm; the preparation method of the B component rapid vulcanizer is as follows: in a planetary mixer, carbon black paste, a crosslinking agent and a viscosity-enhancing silane coupling agent are added respectively, after vacuuming and stirring evenly, a catalyst is added, and vacuuming and stirring are continued. After stirring evenly, the B component rapid vulcanizer is obtained.

[0051] Preferably, the two-component silicone structural sealant for low-temperature construction comprises component A main paste: component B low-temperature rapid vulcanizing agent = 10-14:1 (weight ratio), 8-10:1 (volume ratio).

[0052] Compared with the prior art, the present invention provides a low-temperature fast-vulcanizing two-component silicone structural sealant for building, comprising a main paste of component A and a fast vulcanizing agent of component B. The main paste of component A is prepared by mixing and grinding the following raw materials in parts by weight: 100 parts by weight of 107 glue, 0-20 parts by weight of dimethyl silicone oil, 90-130 parts by weight of nano calcium carbonate, and 0-10 parts by weight of precipitated white carbon black; the fast vulcanizing agent of component B is prepared by mixing the following raw materials in parts by weight: 20-60 parts by weight of carbon black paste, 8-20 parts by weight of crosslinking agent, 5-15 parts by weight of tackifying silane coupling agent, and 0.5-3 parts by weight of catalyst.

[0053] In the present invention, 107 glue and the cross-linking agent form a cross-linked three-dimensional network of polysiloxane; dimethyl silicone oil has a plasticizer effect, which adjusts the viscosity of the adhesive and the operating extrusion process performance, and improves the bonding performance to the substrate; in addition to having a semi-reinforcing effect, nano calcium carbonate improves its compatibility and dispersibility in polysiloxane due to its own weak alkalinity, nanostructure and surface modification, and increases the bonding performance of the adhesive to the substrate; precipitated silica has good reinforcing performance, and after heating and dehumidification, the trace moisture it carries plays a vital role in the deep and rapid vulcanization of the two-component condensation type silicone rubber; in the present invention, an advanced twin-screw continuous production line is used to produce the main paste of component A, reducing the impact of human factors on product quality: automatic metering, screw mixing, grinding, heating, vacuuming (dehumidification and bubble removal), cooling and filtering (removal of mechanical impurities). Product appearance: white and delicate paste, no particles and black spots, stable performance.

[0054] In the present invention, a planetary mixer is used to produce the B component rapid vulcanizing agent. The planetary mixer itself has the vacuum stirring function of scraping the bottom and wall and rotating and revolving. Due to the unique design of the stirring paddle, the material at the bottom of the cylinder can be reversed upward, and the paddle above can press the upward material downward. Therefore, the material can be fully mixed and stirred without dead angles in the planetary mixer. During the stirring process, in order to isolate the influence of moisture in the air on the rapid vulcanizing agent, a vacuum method is adopted to isolate moisture and remove bubbles in the material. When discharging, the product is isolated from the air by nitrogen protection, and filtered and packaged. Product appearance: black, bright and delicate paste, free of impurities, and stable performance.

[0055] In the present invention, the above raw materials are selected and organically matched to interact and promote each other. At the same time, an advanced twin-screw continuous production line is adopted. Through the mixing and grinding of the screw, the uniform dispersion of the filler in the 107 glue is improved, and the agglomeration of the filler in the glue is avoided; the moisture content and bubble-freeness in the main paste are ensured by heating, vacuuming and dehumidifying; the main paste is cooled and filtered to remove the mechanical impurities remaining inside, further ensuring the quality stability of the main paste of component A.

[0056] In the present invention, by optimizing and organically matching the above raw materials, they interact and promote each other, and a planetary mixer is used to prepare the B component rapid vulcanizing agent under normal temperature and negative pressure conditions, thereby avoiding uneven dispersion, stratification and oil leakage of the components, ensuring the mixing uniformity and long-term storage stability of the components, and improving the consistency of product performance.

[0057] The features of the present invention can be clearly understood by referring to the following detailed description of the preferred embodiments. DETAILED DESCRIPTION

[0058] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the present invention is further described.

[0059] The invention provides a low-temperature fast-vulcanizing bonding two-component silicone structural sealant for building bonding and sealing, comprising a component A main paste and a component B fast vulcanizing agent.

[0060] The main paste of component A is prepared by mixing the following raw materials in parts by weight:

[0061]

[0062] The B component rapid vulcanizing agent is prepared by mixing the following raw materials in parts by weight:

[0063]

[0064] The low-temperature fast-vulcanizing bonding two-component silicone structural sealant A component main paste for building bonding and sealing provided by the present invention comprises: 100 parts by weight of 107 glue, wherein the viscosity of the 107 glue is 5000-80000 mPa·s, preferably 20000 mPa·s.

[0065] The low-temperature fast-vulcanizing bonding two-component silicone structural sealant A component main paste for building bonding and sealing provided by the present invention comprises: 0 to 20 parts by weight of dimethyl silicone oil, preferably 15 parts by weight. The viscosity of the dimethyl silicone oil is 100 to 500 mPa·s, preferably 350 mPa·s. In the present invention, the dimethyl silicone oil mainly acts as a plasticizer.

[0066] The main paste of component A of the low-temperature fast-vulcanizing bonding two-component silicone structural sealant for building bonding and sealing provided by the present invention comprises: 90 to 130 parts by weight of nano-calcium carbonate, preferably 105 parts by weight; the surface of the nano-calcium carbonate is treated with stearic acid; in the present invention, the nano-calcium carbonate mainly plays a reinforcing and viscosity-increasing role.

[0067] The present invention provides a low-temperature fast-vulcanizing bonding two-component silicone structural sealant A component main paste for building bonding and sealing, comprising: 0 to 10 parts by weight of precipitated silica, preferably 7 parts by weight. The moisture content of the precipitated silica is about 10%. In the present invention, the precipitated silica mainly plays a reinforcing and hydrating role, and a more important role is that through its own bound water, after the twin-screw mixing, grinding, heating and vacuuming process, a trace amount of water is evenly dispersed in the main paste and stored stably for a long time, which promotes the rapid deep vulcanization and viscosity increase of the two-component silicone structural sealant.

[0068] The invention provides a low-temperature fast-vulcanizing bonding two-component silicone structural sealant for building bonding and sealing, wherein the B-component fast-vulcanizing agent comprises: 20 to 60 parts by weight of carbon black paste, preferably 40 parts by weight.

[0069] In the present invention, the carbon black paste is preferably produced according to the following process: 350 mPa·s dimethyl silicone oil and carbon black are mixed in a weight ratio of 4:1, twin-screw grinding, heating at 150°C, vacuum degree lower than -0.08 MPa, vacuum dehumidification and degassing, and filtering to obtain a bright black and fine carbon black paste.

[0070] The invention provides a low-temperature fast-vulcanizing bonding two-component silicone structural sealant B component fast vulcanizing agent for building bonding and sealing, comprising: 8 to 20 parts by weight of a cross-linking agent, preferably 8 to 12 parts by weight; the cross-linking agent is an alkyl triethoxysilane oligomer, preferably methyl triethoxysilane oligomer, hexamethoxydisiloxane or hexaethoxydisiloxane; in the invention, the alkoxy oligomer is used as a cross-linking agent, firstly, to reduce the water required for the hydrolysis of the alkoxy group, secondly, to accelerate the reaction rate and quickly improve the strength under the promotion of the alkaline amino group, thirdly, to reduce the cross-linking density and improve the elongation, and fourthly, to reduce the generation of alcohol volatiles.

[0071] The invention provides a low-temperature fast-vulcanizing bonding two-component silicone structural sealant B component fast-vulcanizing agent for building bonding and sealing, comprising: 5 to 15 parts by weight of a tackifying coupling agent, preferably 8 to 12 parts by weight; the tackifying silane coupling agent is a compound of an oligomer containing an amino silane coupling agent and a silane coupling agent containing an epoxy group; the oligomer containing an amino silane coupling agent is selected from: γ-aminopropyl trimethoxysilane, methyl γ-aminopropyl dimethoxysilane, γ-aminopropyl triethoxysilane, methyl γ-aminopropyl diethoxysilane, N-(β-aminoethyl)-γ-aminopropyl trimethoxysilane, methyl N-(β-aminoethyl)-γ-aminopropyl dimethoxysilane, N-(β- A compound of one or more oligomers of bis-(3-trimethoxysilylpropyl)amine and bis-(3-triethoxysilylpropyl)amine; a silane coupling agent containing an epoxy group: a compound of one or more oligomers of γ-glycidyloxypropyl trimethoxysilane, methyl γ-glycidyloxypropyl dimethoxysilane, γ-glycidyloxypropyl triethoxysilane and methyl γ-glycidyloxypropyl diethoxysilane; aminosilane coupling agent hydrolyzed oligomer: aminodialkylsilane: epoxysilane coupling agent = 2:1:2 (weight ratio).

[0072] Adhesives containing amino and epoxy group-enhanced silane coupling agents have obvious bonding effects on substrates: first, the role of their own adhesion-enhancing functional groups; second, the number of amino adhesion-enhancing groups is increased through prepolymerization; third, the combination of primary and secondary amines promotes the ring-opening adhesion of epoxy groups; and fourth, alkaline amino groups promote the rapid reaction and vulcanization of cross-linking agents.

[0073] The method for synthesizing the amino-containing silane coupling agent oligomer comprises the following steps:

[0074] (1) first add a polar solvent into a reaction vessel;

[0075] (2) then adding the aminosilane coupling agent into the reaction vessel and starting the stirrer to allow the silane coupling agent to fully dissolve;

[0076] (3) adding a solution of pure water dissolved in a polar solvent dropwise into a reaction vessel, controlling the dropping speed so that the reaction temperature of the hydrolysis polymerization of the aminosilane coupling agent is maintained in the range of 45 to 50° C.;

[0077] (4) After the polar solvent solution containing water is added dropwise, the temperature of the solution in the reaction container is raised to about 90° C. and reacted for 2 hours;

[0078] (5) Finally, the solution temperature was raised to about 120° C., and the reaction was continued for 2 hours. The vacuum degree was controlled to be lower than -0.09 MPa, and the solution was vacuumed to obtain an aminosilane coupling agent oligomer with a degree of polymerization of 6.

[0079] The invention provides a low-temperature fast-vulcanizing bonding two-component silicone structural sealant B component fast vulcanizing agent for building bonding and sealing, comprising: 0.5 to 3 parts by weight of a catalyst, preferably 0.6 to 2 parts by weight; the catalyst is organic tin and organic titanium; the organic tin catalyst is selected from: one or more of dibutyltin dilaurate, dioctyltin dilaurate, dimethyltin dilaurate, dibutyltin diacetate and dibutylbis(acetylacetonate)tin; the organic titanium catalyst is selected from: one or more of isopropyl titanate, n-butyl titanate, diisopropyl diacetylacetate titanate and diacetylacetate titanate 1.3-propylene glycol.

[0080] The present invention provides a method for preparing the low-temperature fast-vulcanizing bonding two-component silicone structural sealant for building bonding and sealing, comprising the following steps:

[0081] The main paste of component A is produced according to the following production process:

[0082] 107 glue, dimethyl silicone oil, nano calcium carbonate and precipitated silica are transported to the twin-screw continuous production line through pipelines after passing through an automatic metering system. After mixing, grinding, heating, vacuuming (dehumidification and defoaming), cooling and filtering (removal of mechanical impurities), the main paste of component A is obtained.

[0083] The twin-screw production process: temperature 120±5℃, vacuum degree lower than -0.08MPa, stainless steel filter mesh size 100 mesh or more. The product is tested by a 50-micron scraper: Product appearance: white and delicate paste, free of particles and other mechanical impurities. The moisture content is tested by a Karl Fischer moisture tester: 800±50ppm. The B component rapid vulcanizer is produced and prepared according to the following production process:

[0084] The carbon black paste, the cross-linking agent and the tackifying coupling agent are added into a planetary mixer respectively, and after vacuuming and stirring evenly, the catalyst is added, and the vacuuming and stirring are continued. After stirring evenly, component B is obtained.

[0085] Specific preparation process: Under normal temperature conditions, first replace the material cylinder with nitrogen, then add carbon black paste, cross-linking agent and viscosity-increasing coupling agent in turn, the vacuum degree is lower than -0.08MPa, vacuum and stir for 40 to 60 minutes, fill with nitrogen and add catalyst, the vacuum degree is lower than -0.08MPa, continue to vacuum and stir for 30 to 40 minutes, filter with a 100-mesh stainless steel mesh, product appearance inspection: black, bright and delicate paste, free of impurities.

[0086] The two-component silicone structural sealant for low-temperature construction comprises a main paste component A and a low-temperature rapid vulcanizing agent component B in a ratio of 10 to 14:1 (weight ratio) and 8 to 10:1 (volume ratio).

[0087] The technical solution of the low-temperature fast-vulcanizing two-component silicone structural sealant for construction provided by the present invention is further illustrated below in conjunction with embodiments. Those skilled in the art should understand that the examples described are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0088] Example 1.

[0089] Preparation of the main paste of component A: 107 glue with a viscosity of 20000mPa·s, dimethyl silicone oil with a viscosity of 350mPa·s, nano-calcium carbonate and precipitated silica are weighed by an automatic metering system and transported to a twin-screw continuous production line through a pipeline. The desired product is obtained through twin-screw mixing and grinding, heating, vacuuming (dehumidification and defoaming), cooling and filtering (removal of mechanical impurities).

[0090] Preparation of component B rapid vulcanizing agent: add carbon black paste, crosslinking agent and viscosity-enhancing silane coupling agent into a planetary mixer respectively, vacuum and stir evenly, then add the catalyst, continue vacuuming and stirring, and after stirring evenly, filter to obtain the desired product.

[0091] Preparation example of aminosilane coupling agent oligomer, its synthesis method:

[0092] (1) First, add 120 g of methanol solvent into a reaction vessel;

[0093] (2) Then, 120 g of N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane was added to the reaction vessel, and the stirrer was turned on to allow the silane coupling agent to fully dissolve.

[0094] (3) A mixed solution of 9.5 g of pure water, 50 g of methanol and 0.5 g of ethylenediamine was added dropwise to the reaction container. The dropping speed was controlled so that the reaction temperature of the hydrolysis polymerization of the aminosilane coupling agent was maintained in the range of 45 to 50°C.

[0095] (4) After the mixed solution is added dropwise, the solution in the reaction container is heated to about 90°C and reacted for 2 hours. (5) Finally, the temperature of the reaction solution is raised to 120°C and the reaction is continued for 2 hours. After the vacuum degree is lower than -0.09 MPa, the solvent is evaporated under reduced pressure to obtain an aminosilane oligomer with a degree of polymerization of 6.

[0096] The contents of the above raw materials are shown in Table 1. The properties of the two-component silicone structural sealant prepared in this embodiment and its vulcanized sealant were tested, and the test results are shown in Table 2.

[0097] Table 1 is a formula table of the two-component silicone structural sealant of this embodiment.

[0098]

[0099] Table 2 is a table of measured performance data of the two-component silicone structural sealant and the vulcanized rubber in Example 1.

[0100]

[0101] Example 2.

[0102] The preparation formula of the main paste of component A is shown in Example 1.

[0103] The preparation formula of component B fast curing agent is shown in Table 3.

[0104]

[0105] Table 4 is a table of measured performance data of the two-component silicone structural sealant and the vulcanized rubber in Example 2.

[0106]

[0107] Example 3.

[0108] The preparation formula of the main paste of component A is shown in Example 1.

[0109] The preparation formula of component B fast curing agent is shown in Table 5.

[0110]

[0111] Table 6 is a table of measured performance data of the two-component silicone structural sealant and the vulcanized rubber in Example 3.

[0112]

[0113] Example 4.

[0114] The preparation formula of the main paste of component A is shown in Example 1.

[0115] The preparation formula of component B fast curing agent is shown in Table 7.

[0116]

[0117] Table 8 is a table of measured performance data of the two-component silicone structural sealant and the vulcanized rubber in Example 4.

[0118]

[0119]

[0120] Example 5

[0121] The preparation formula of the main paste of component A is shown in Example 1.

[0122] The preparation formula of component B rapid vulcanizing agent is shown in Table 9.

[0123]

[0124] Table 10 is a table of measured performance data of the two-component silicone structural sealant and the vulcanized rubber in Example 5.

[0125]

[0126] Example 6.

[0127] The preparation formula of the main paste of component A is shown in Example 1.

[0128] The preparation formula of component B rapid vulcanizing agent is shown in Table 11.

[0129]

[0130]

[0131] Table 12 is a table of measured performance data of the two-component silicone structural sealant and the vulcanized rubber in Example 6.

[0132]

[0133] Comparative Example 1

[0134] The preparation formula of the main paste of component A is different from that of Example 1 in that no precipitated silica is added, and the other raw material formulas and production processes remain unchanged. See Table 13.

[0135]

[0136] The preparation formula of the rapid vulcanizing agent of component B is the same as that of Example 1.

[0137] Table 14 is a table of measured performance data of the two-component silicone structural sealant and vulcanized rubber of Comparative Example 1.

[0138]

[0139]

[0140] Comparative Example 2

[0141] The raw material formula and production process of the main paste of component A are the same as those in Example 1.

[0142] The preparation formula of the curing agent of component B is different from that of Examples 1 to 6 in that the crosslinking agent is tetraethyl orthosilicate, the catalyst is dibutyltin dilaurate, and the other raw material formulas and production processes remain unchanged. See Table 15.

[0143]

[0144] Table 16 is a table of measured performance data of the two-component silicone structural sealant and vulcanized rubber of Comparative Example 2.

[0145]

[0146] Comparative Example 3

[0147] The formula and production process of the main paste of component A are the same as those in Example 1.

[0148] The preparation formula of the curing agent of component B is different from that of Examples 1 to 6 in that the crosslinking agent is tetraethyl orthosilicate, the aminosilane coupling agent is a conventional aminosilane coupling agent, the catalyst is dibutyltin dilaurate, and the other raw material formulas and production processes remain unchanged. See Table 17.

[0149]

[0150] Table 18 is a table of measured performance data of the two-component silicone structural sealant and vulcanized rubber of Comparative Example 3.

[0151]

[0152] Comparative Example 4

[0153] The formula and production process of the main paste of component A are the same as those of comparative example 1.

[0154] The preparation formula of the curing agent of component B is different from that of Examples 1 to 6 in that the aminosilane coupling agent is a conventional aminosilane coupling agent, the catalyst is dibutyltin dilaurate, and the other raw material formulas and production processes remain unchanged, as shown in Table 19.

[0155]

[0156]

[0157] Table 20 is a table of the measured performance data of the two-component silicone structural sealant and vulcanized rubber of Comparative Example 4.

[0158]

[0159] It can be seen from Examples 1 to 6 that the two-component silicone structural sealant of the present invention has a tensile bond strength in a 24-hour test under winter construction conditions that has reached the mandatory requirements of the national standard GB16776, and meets about 70% of the tensile bond strength value after 14 days of curing under the same environmental conditions, and can be constructed under low temperature conditions in winter.

[0160] Due to the great differences in building materials and construction environments, the actual use of silicone structural sealants should be strictly in accordance with the silicone structural sealant usage specifications: compatibility test, butterfly test, pull-off test and rubber tapping test before installation must be fully performed to ensure the quality and safety of curtain wall glass installation.

[0161] The above description is only an explanation of the present invention, not a limitation of the present invention. It should be noted that, for those skilled in the art, several improvements and modifications can be made without departing from the principles of the present invention, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. Low temperature fast vulcanizing two-component silicone structural sealant for construction, characterized by: The two-component silicone structural sealant is composed of a main paste component A and a low-temperature rapid vulcanizing agent component B: The main paste of component A: α, ω-dihydroxy polydimethylsiloxane (commonly known as 107 glue), nano calcium carbonate, precipitated white carbon black and dimethyl silicone oil are prepared through a twin-screw continuous production line to obtain a product with stable performance; Component B low temperature rapid vulcanizing agent: carbon black paste, cross-linking agent, viscosity-enhancing silane coupling agent and catalyst.

2. The main paste of component A according to claim 1, characterized in that: The main paste component of component A is prepared by mixing the following raw materials in parts by weight: 107 glue 100 parts by weight Dimethyl silicone oil 0-20 parts by weight 90-130 parts by weight of nano calcium carbonate 0 to 10 parts by weight of precipitated silica.

3. The main paste of component A according to claim 1, characterized in that: The viscosity of the 107 glue is 5000-80000 mPa·s, and the viscosity of the dimethyl silicone oil is 100-500 mPa·s.

4. The main paste of component A according to claim 1, characterized in that: The nano calcium carbonate is nano calcium carbonate whose surface is treated with stearic acid.

5. The main paste of component A according to claim 1, characterized in that: The water content of the precipitated silica is about 10%.

6. The main paste of component A according to claim 1, characterized in that: By adding the bound water of precipitated silica, adopting a twin-screw continuous production line, twin-screw mixing and grinding, high-temperature heating at 120±5℃, vacuum degree lower than -0.08MPa, vacuuming (dehumidification and defoaming), cooling and filtering (removing mechanical impurities), a fine main paste component A containing trace and stable deep rapid vulcanization accelerator water is obtained.

7. The main paste of component A according to claim 1, characterized in that: The moisture content of the main paste is about 800±50ppm.

8. The low-temperature rapid vulcanizing agent of component B according to claim 1, characterized in that: The B component low temperature rapid vulcanizing agent is prepared by mixing the following raw materials in parts by weight: Carbon black paste 20-60 parts by weight Crosslinking agent 8-20 parts by weight 5-15 parts by weight of adhesion-enhancing silane coupling agent Catalyst 0.5-3 parts by weight.

9. The low-temperature rapid vulcanizing agent of component B according to claim 1, characterized in that: The crosslinking agent is composed of alkyltrimethoxysilane or alkyltriethoxysilane oligomer, hexamethoxydisilylethane or hexaethoxydisilylethane; Alkyl trimethoxysilane oligomer selection: one or more combinations of methyl trimethoxysilane, ethyl trimethoxysilane or propyl trimethoxysilane oligomer; The alkyltriethoxysilane oligomer is selected from one or more combinations of methyltriethoxysilane, ethyltriethoxysilane or propyltriethoxysilane oligomers.

10. The low-temperature rapid vulcanizing agent of component B according to claim 1, characterized in that: The adhesion-enhancing silane coupling agent is a compound of an amino-containing silane coupling agent oligomer and an epoxy-containing silane coupling agent; Selection of oligomers containing amino silane coupling agents: γ-aminopropyltrimethoxysilane, methylγ-aminopropyldimethoxysilane, γ-aminopropyltriethoxysilane, methylγ-aminopropyldiethoxysilane, N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane, methylN-(β-aminoethyl)-γ-aminopropyldimethoxysilane, N-(β-aminoethyl)-γ-aminopropyltriethoxysilane, hydrolyzed oligomers of methylN-(β-aminoethyl)-γ-aminopropyldiethoxysilane and bis-(3-trimethoxysilylpropyl)amine, a compound of one or more oligomers of bis-(3-triethoxysilylpropyl)amine; Selection of epoxy group-containing silane coupling agent: one or more combinations of γ-glycidyloxypropyl trimethoxysilane, methyl γ-glycidyloxypropyl dimethoxysilane, γ-glycidyloxypropyl triethoxysilane, and methyl γ-glycidyloxypropyl diethoxysilane; Aminosilane coupling agent oligomer: aminodialkylsilane: epoxysilane coupling agent = 2:1:2 (weight ratio).

11. The low-temperature rapid vulcanizing agent of component B according to claim 1, characterized in that: The method for synthesizing the amino-containing silane coupling agent oligomer comprises the following steps: (1) First add the polar solvent into the reaction vessel; (2) Then add the aminosilane coupling agent into the reaction vessel and start the stirrer to allow the coupling agent to fully dissolve; (3) adding a solution of pure water dissolved in a polar solvent dropwise into a reaction vessel, controlling the dropping speed so that the reaction temperature of the hydrolysis polymerization of the aminosilane coupling agent is maintained in the range of 45 to 50°C; (4) After the polar solvent solution containing water is added dropwise, the temperature of the solution in the reaction vessel is raised to about 90° C. and the reaction is continued for 2 hours; (5) Finally, the solution temperature was raised to about 120°C, and the reaction was continued for 2 hours. The vacuum degree was controlled to be lower than -0.09 MPa, and the solution was vacuumed to obtain an aminosilane coupling agent oligomer with a degree of polymerization of 6.

12. The low-temperature rapid vulcanizing agent of component B according to claim 1, characterized in that: The catalyst is organic tin and organic titanium; Selection of organic tin catalyst: one or more of dibutyltin dilaurate, dioctyltin dilaurate, dimethyltin dilaurate, dibutyltin diacetate and dibutyltin bis(acetylacetonate); The organic titanium catalyst can be selected from one or more of isopropyl titanate, n-butyl titanate, diisopropyl diacetoacetate titanate and 1,3-propylene diacetoacetate titanate.

13. The low-temperature rapid vulcanizing agent of component B according to claim 1, characterized in that: In a planetary mixer, add carbon black paste, cross-linking agent and tackifying coupling agent respectively, vacuum and stir evenly, then add catalyst, continue vacuum and stir, and obtain component B after stirring evenly.

14. The low-temperature fast-vulcanizing two-component silicone structural sealant for construction according to claim 1, characterized in that: The two-component silicone structural sealant has a main paste component A: a low-temperature rapid vulcanizing agent component B = 10-14:1 (weight ratio), 8-10:1 (volume ratio).

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